Cathode ray tube member



March 14, 1961 E, POHLE 2,975,321

CATHODE RAY TUBE MEMBER Filed July l. 1954 INVENTOR.

ERIC POHLE A T TORNEYS nit f carnonn RAY rune MEMBER Filed `luly 1, 1954, Ser. No. 440,592

8 Claims. (Cl. 313-255) This invention relates to positioning structures for electrode assemblies in electron discharge devices and particularly to electron gun centering structures in cathode ray tubes.

The present invention is an improved modification of the centering device disclosed by Herndon W. Leighton in United States Patent 2,656,481. The improved structure reduces the force required to insert an electrode assembly into the neck of an electron discharge device even though the stiffness of resilient metal strip positioning member attached to the assembly is increased. In addition, the improved structure comprises an outwardly liared spring linger to make contact with a conductive coating on the inner wall of the electron discharge device at a point removed from the electrode assembly. In the case of cathode ray tubes, where the electrode assembly is a gun having electron lenses, thevspring'lingers on the resilient position members serve to contact the usual conductive coating on the inner wall of the tube at a point so far removed from the electron lenses as to have no eliect on the electron lenses.

The improved structure comprises a resilient member attached to a flange on the electrode assembly. A gableshaped slot is formed in the resilient member, and notches are provided in the rim of the flange to interlock with the ends of the slot and hold the resilient member in place. By providing a gable-shaped slot, the resilient member is allowed to pivot about the axis determined by the location of the notches to tilt the electrode assembly inwardly and allow it to be inserted into the neck opening more easily. This limited liaccidity of the resilient members is especially useful when pairs of metal strips having outwardly flared spring fingers are used to center the electrode assembly. Pivoting of the strips brings the outer ends of the spring lingers inwardly so that they may be l easily slipped into the flared neck opening of the discharge device. Once the spring fingers are inside the neck and the metal strips are started into the opening, pressure by the inner neck wall on the ends of the metal strips pivots the centering devices in the reverse direction about the aforementioned axis and forces the spring lingers into contact with the neck wall.

It is one object of the present invention to provide an improved centering device for electron guns.

Other objects are to provide a centering device having a gable-shaped slot to facilitate entry of the centering device into the neck of a cathode ray tube and to provide for extra spring pressure of the centering device against the inner neck wall of the tube by means of an outwardly flared spring finger.

Further objects will be apparent after studying the following specilication, together with the drawings in which,

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Fig. 3 shows a cross-section through 3 3 of the tube in Fig. 1 with one centering device removed; and

Fig. 4 shows a portion of `the tube illustrating the electron gun in Fig. 1 being introduced into the neck thereof.

Fig. 1 shows a cathode ray tube 11 having an electron gun located therein. The electron gun i-s mounted on a stem 12 by means of a plurality of support wires 13. 'I'he gun comprises, in order, a control grid 14, a second grid 16, and an anode 17, all secured to a pair of support rods of which only the rod 18 appears in the drawing. An electrostatic electron lens structure of the type shown in a copending application, Serial No. 249,120, by Kenneth A. Hoagland, is attached to one end of the anode 17. This electrostatic focusing structure comprises a focus electrode 19 and a limiting electrode 21, which are supported partly by a plurality of insulating rods 22, extending from the anode 17 and partly by a lpair of resilient centering devices 23. Each of the centering devices 23 has a spring linger 24 extending from one side of the main portion thereof making contact with a conductive coating 25 on the inner wall of the neck of tube 11.

One of the spring centering devices 23- is shown more clearly in Fig. 2. This centering device comprises a main resilient portion 26 having a gable-shaped slot 28 and an outwardly extending spring linger 24. The main l portion 26 has a plurality of rounded protuberances 27 Fig. l shows a longitudinally cutaway section of a cath- Fig. 2 isa plan view of the electron gun centering device of Fig. 1

pressed therein.

The outwardly extending flange 20y of the focusing electrode 21 fits into the slot 28 in interlocking fashion, as shown most clearly in Fig. 3, and is provided with a plurality of pairs of slots therein spaced apart along the outer periphery of the flange but angled inward to provide a better gripping surface for the ends of the slot 28 in the centering device 23. In assembling the electron gun, the outer ends of the transverse portion 26 of the centering device 23 are manipulated, either pulled apart or pushed together, so as to increase the distance between the ends of the slot 28 and allow the ends thereof to slip into, and interlock with, the notches 29v in the flange 20. When the electron gun is finally introduced into the cathode ray tube 11, the protuberances 27 and the spring lingers 24 press against the inner wall of the neck of tube 11, as shown in Fig. l, and thereby position the front end of the electron gun.

Fig. 4 shows the manner in which the electron gun is introduced into the neck of tube 11. In this ligure the gable or wedge shape of the slot 28 in the electron gun centering device 23 is shown. The centering devices 23 are shown as pivoted inwardly, as may easily be done because of the width of t-he slot 28, particularly at the middle thereof, to allow the spring lingers 24 to slip easily into the neck of tube 11 and also to allow the ends of the main portions 26 of the centering devices 23 to facilitate entry into the neck of tube 11. As the electron gun is pushed farther into the' neckof tube 11, the centering device 23 tends to rotate around pivots provided by the slots 29 in flange 20 so as to force the spring lingers 24 lirmly into contact with the neck of tube 11 and to position the protuberances27 in alignment with the neck of tube 11 as shown in Fig. l. In this manner, the diiculty of introducing the electron gun into the neck is considerably reduced while, at the same time, the spring lingers 24 may have' suliicient stiness to assure that once the tube is assembled there will be good electrical contact between the lield limiting electrode 21 and the conductive coating 25, as shown in Fig. l. The liaccidity of the assembly, which was useful in inserting the electron gun into the neck 'of tube 11, has been replaced, because of the pressure of protuberances 27 and spring lingers 24 against the neck wall of tube 11, by a tautness which will not be adversely aected by any future heating or mechanical manipulation of the tube.

Although the slot has been designated as gable-shaped, it will be apparent lthat any shape having greater width in the middle than at the ends will be in accordance with the invention, and this and other modifications may be made in the structure without departing from the scope of the following claims.

What is claimed is:

l. A positioning structure for an electron discharge device comprising an electrode structure having a flange extending substantially radially outwardly, said llange having a pair of notches in the periphery thereof, spaced apart by a chordal distance; a resilient member hinged to said flange by means of a slot therein formed so that the chordal distance between the ends of said slot is different from the chordal distance between said notches, said member being characterized by a lateral flexibility sucient to change the chordal distance between the ends of said slot to equal the chordal distance between said notches so that the portion of said llange between said notches may be inserted in said slot and the ends of said slot retained in interlocking relationship with said notches, said slot being defined by sides which are bowed so that the middle of said slot has a width greater than the ends thereof to permit a limited amount of free pivotal movement of said member about an axis through said notches.

2. A positioning structure for an electron discharge device having a substantially 4tubular portion, said positioning structure comprising an electrode structure having a iiange extending substantially radially outwardly toward the inner wall of Said substantially tubular portion; said ange having a plurality of pairs of notches in the periphery thereof, the two notches in each pair being spaced apart by a chordal distance; a plurality of resilient members hinged to said ange, each of said members having a slot therein and being formed so that the chordal distance between the ends of said slot is less than the chordal distance between the notches of each of said pairs of notches, each said member being characterized by a flexibility suiiicient to increase the chordal distance between the ends of each respective said slot to equal the chordal distance respectively between the notches in each of said pairs, each said resilient member being attached to said ilange so that a portion of said ange between the notches of each of said pairs respectively extends through each said slot and the ends thereof are retained in interlocking relationship with the said notches; a resilient projection extending from one side of each said member in a direction generally parallel to the longitudinal axis of said discharge device but tilted outwardly from said axis, each said slot being dened by longitudinal sides of which the side proximal to said projection is bowed out so that the middle of said slot has a width greater than the ends of said slot to allow a limited amount of hinge-like rotation of each said member about an axis through said notches.

3. A positioning structure for an electron discharge device having a substantially tubular portion, said positioning structure comprising an electrode structure having a flange extending substantially radially outwardly toward the inner wall of said substantially tubular portion; said ange having a pair of notches in the periphery thereof, the two notches in said pair being spaced apart by a chordal distance; a resilient member having a slot therein and being formed so that the chordal distance between the ends of said slot is less than the chordal distance between the notches of said pair, said member being characterized by a flexibility sufiicient to increase the chordal distance between the ends of said slot to equal the chordal distance between the notches of said pair, said resilient member being attached to said flange so that a portion of said ange between the said notches extends through said slot and the ends of said slot are retained in interlocking relationship with the said notches; a resilient projection extending from one side of said member in a direction generally perpendicular to the longitudinal dimension of said slot, said slot being delined by longitudinal sides of which the side proximal to said projection is bowed out so that the middle of said slot has a width greater than the ends of said slot to allow hinge-like rotation of said member in one direction about an axis through said notches, and the longitudinal side of said slot distal from said projection is straight so as to prohibit rotation of said member in the opposite direction. l

4. A positioning structure for an electron gun in the neck of a cathode ray tube, said structure comprising an element of said gun having a laterally extending flange, said flange having a pair of notches in the periphery thereof, the notches being spaced apart by a chordal distance; a resilient member having a slot therein and being resiliently curved longitudinally of said slotso that the chrdal distance between the ends of said slot is less than the chordal distance between the notches of said pair, said member being attached to said flange so that they portion of said flange between the notches of said pair is inserted into said slot and the ends of said slot are held in interlocking relationship with said notches, the resilient curvature of said member being such as to force the ends thereof into contact with the inner wall of said neck, said member having reverse curves at the outer ends thereof to present smooth surfaces to said inner wall; a resilient projection on said member projecting in a direction generally longitudinally of said tube and bent Youtwardly to press against said inner wall thereof, said slot being defined by a gabled longitudinal side proximal to said projection and a fiat longitudinal side distal from said projection so that the middle portion of said slot iswider than the end portions thereof to allow said resilient member a limited amount of hingelike rotation about a transverse axis through said pair of notches.V

5. A positioning structure for an electron gun in the neck of a cathode ray tube, said structure comprising a resilient member having a slot therein and being resiliently curved longitudinally of said slot, the resilient curvature of said member being such as to force the ends thereof into contact with the inner wall of said neck, said member having reverse curves at the outer ends thereof to present smooth surfaces to said inner wall; a resilient projection on said member projecting in a direction generally longtiudinally of said tube and bent outwardly to press against said inner wall thereof, said slot being defined by a gabled longitudinal side proximal to said projection and a at longitudinal side distal from said projection so that the middle portion of said slot is wider than the end portions thereof to allow said resilient member to rotate about a transverse axis.

6. A positioning structure for an electron discharge device having a substantially tubular portion, said positioning structure comprising an electrode structure having a flange extending substantially radially outward toward the inner wall of said substantially tubular portion; a plurality of pairs of notches in the periphery of said ange, the two notches in each pair being spaced apart by a chordal distance; a plurality of resilient members, each of said lmembers having a slot therein and being formed so that the chordal distance between the ends of said slot is less than the chordal distance between the notches of one of said pairs of notches, said member being characterized by a flexibility sul'licient to increase the chordal distance between the ends of said slot to equal the chordal distance between the notches in one of said pairs, said resilient member being attached to said ange so that a portion of said flange between one of said pairs of notches extends through said slot and the ends of said slot are retained in interlocking relationship with the notches of said pair; a resilient projection extending from one side of said member in a direction generally perpendicular to the longitudinal dimension of said slot, said slot having at the center thereof a width greater than the thickness of said ange, to allow a limited amount of hinge-like rotation of said member about an axis through said notches, said member extending on the side of said slot distal from said projection to make contact with said inner wall and force said projection outwardly into contact with said inner wall.

7. A device for positioning an electron gun in the neck of a cathode ray tube, comprising: a T-shaped element having a longitudinal section and a transverse section, said transverse section having a slot whose shape approximates a segment of a circle; mounting means causing said element to pivot about the chord of said slot whereby the end of said longitudinal section may move away from the inner wall of said neck to facilitate inserting said gun into said neck; and means causing the end of said transverse sectionto press against said inner wall whereby said element is caused to pivot about said chord to move said end of said longitudinal section to press against said Wall.

8. In an electron gun for a cathode ray tube, an electrode and a centering device therefor, said centering device comprising a plate attached to said electrode and extending radially outward thereform, and a resilient metal strip member, said member being generally V- shaped at its center portion and having a longitudinal slot therein and bowed end portions presenting a rounded surface on the outer ends thereof, said resilient member being attached to said plate with a portion of the end of said plate extending through said slot, and an elongated tinger attached to the V-shaped portion of said strip member and extending substantially normal to the longitudinal axis thereof, said elongated finger having a first portion thereof attached to and immediately adjacent said V-shaped portion having a V-shaped cross section and a second portion constituting an extension of said first portion, said second portion being bent away from the axis of said first portion at the point of attachment thereto and being reversely bent at its outer end.

References Cited in the file of this patent UNTTED STATES PATENTS 1,831,416 Junkers Nov. l0, 1931 2,323,140 Lane June 29, 1943 2,656,481 Leighton Oct. 20, 1953 

